Saturday, October 11, 2014

Tour Divide 2015 - Contact Part 2: Butt

There is nothing quite like the exquisite misery that is delivered by a saddle sore.  It's one of those things where you think you can keep pushing, just muscle through the pain, not realizing you're opening yourself up to an infection that can take you out of the game for days, if not weeks.

There are several things you can do to reduce the possibility of toxic ass-et syndrome: shorts and padding, chamois cream, training mileage, personal hygiene, and the saddle.

Ah, the saddle.

Berthoud Aspin.  As seen on eBay.
I've already mentioned how when I bought my bike, I allowed vanity to enter into my saddle selection, and bought a Gilles Berthoud Aspin touring saddle.  It was a thing of beauty.  But it never quite felt right.  When I went for my bike fitting, I discovered why.

Stephen Merz at Cyclologic is my bike fitter, and one of the services Cyclologic provides is saddle pressure analysis.  With the bike mounted in a trainer, he slips this electronic boot thingy over the saddle, you get on and start to pedal.  As you pedal, he can see in real time where pressure is loading and unloading on the saddle through the cycle of the pedal stroke.  If there are any potentially hazardous pressure points - i.e. under the sit bones - he can see it on his screen.

Before we continue, a little anatomy lesson: what are "sit bones?"

Sit bones (ischial tuberosities) are the part of the pelvis you sit on.  Think of them like the curved runners on a rocking chair.  When you sit erect on a chair, you're actually tipped up on the rear points of the rocking chair runners.  This upright posture isn't so bad because the seat of the chair has enough surface area to disperse pressure to the rest of your butt and thighs, and allows you to move around when you get uncomfortable.  Not so on a bike saddle.  When you sit upright on a bike saddle, the rear points of the sit bones exert pressure on the tissue between the bones and the saddle.

This video shows a tale of two saddles.  My two saddles in fact.  The one on the right is the Berthoud.  As it plays, you'll notice that there are three major pressure points, and they don't move around much.  The points on the left and right are under the rear ends of the sit bones, and the fact that they don't move around tells me that the tissue between the bones is not being unloaded during the pedal stroke, and is therefore less able to recover as I ride.  Concentrated pressure over time leads to tissue fatigue and eventually to saddle sores.  Ouch.

This could be mitigated if I were able to roll my pelvis forward on the saddle as I ride, off of the rear "tips" and onto the longer "runners."  In this position, the shape of the sit bones allows for a wider dispersion of pressure, and the motion of the pedal stroke should allow the sit bones to rock back and forth, allowing for pressure to load and unload on any given point.  But I'm unable to lean forward on this saddle because of the third pressure point.  The one in the middle.  If I were to roll forward on the pelvis, I'd be increasing pressure in the, um, center area.  Such pressure can lead to more than just saddle sores.

Cobb Randée.
So Stephen introduced me to the Randée, a new saddle from Cobb specifically designed for folks doing brevet-style all-day-in-the-saddle kind of events.  I spent one hour on a trainer with Randée, and immediately put my Berthoud up on eBay.  In the video above, Randée is the saddle on the left.  The shape of the Randée allows me to roll my pelvis forward onto the "rockers" of the sit bones, reducing concentrated pressure on the tissue supporting the pelvis without increasing pressure in the middle.  The pressure points that do flare up during the pedal stroke tend to move around, which shows that the tissue beneath the sit bones is better able to unload - and get some relief - during each pedal stroke.  Overall, a much better scenario for long days in the saddle.

For chamois cream, DZ Nuts comes highly recommended, so I'm trying that out.  For shorts, I'm currently wearing DeSoto 400 Mile shorts, which have a 14mm (!) pad, and some high-tech wizardry involving tiny embedded ceramic beads to reduce friction between the saddle and the shorts.  The best part, though, is that they actually provide a degree of compression - more so than typical riding shorts - which is supposed to help stave off muscle fatigue.  So far, I like them.  Order large though - these things are snug!

Everyone's anatomy is unique.  I really wanted the Berthoud saddle to be the one for me, but sometimes things just don't fit together the way we want them to.  I can't recommend one saddle or pair of shorts over another to anybody.  But I absolutely recommend a saddle pressure analysis like the one performed by Cyclologic.  In my view, it's an essential part of the fitting process.


No comments:

Post a Comment